Conjugate heat transfer in solar collector panels with internal longitudinal corrugated fins-Part II: Local results

Abstract

A computational study is conducted to determine, for laminar flow in a solar collector panel or a parallel-plate channel with an internal, longitudinal, corrugated fin, the effects of varying the fin angle (or the fin pitch), the fin thickness, the wall-to-fluid thermal conductivity ratio, and the thermal boundary condition on the local surface temperature and heat flux distributions. The corrugated fin and the two walls form individual triangular flow passages in the collector panel or parallel-plate channel. The results of the investigation show that the variation of the local surface temperature is large when the fin is thin and when the wall/fluid thermal conductivity ratio is small. The local surface heat flux is low near the corners of both the upper and lower triangular flow passages. Near the point of fin attachment on the heated wall, heat may be transferred from the fluid to the fin. Heat may also be transferred from the fluid to the unheated wall near the point of fin attachment. When the thermal conductivity ratio is small, the temperature field in the flow cross section is predominantly stratified. In the limit as the thermal conductivity ratio approaches infinity, the temperature field is that of the thermally fully developed laminar flow in a triangular duct with a streamwise uniform heat flux and peripheral uniform surface temperature boundary condition.